This disclosure generally relates to belt conveyor equipment for bulk material transportation. More specifically, the present disclosure relates to a conveyor belt support assembly for a load zone of bulk material transportation equipment.
Belt conveyors are employed to transport bulk material, such as sand, gravel and the like, from a feed end of a conveyor system, where the material is deposited on the belt, to the opposite end of the conveyor system, where the material is discharged from the belt. Most belt conveyors employ a form of endless belt that is wrapped over a motor-driven head pulley mounted on a frame of the conveyor system at the discharge end and a return idler pulley mounted on the conveyor system frame at the feed end. Between the feed end and the discharge end, the belt is supported on a plurality of troughing idler assemblies that are mounted periodically along the frame of the conveyor.
A series of troughing idler frames or supports 10 are shown in FIG. 1, each idler frame 10 including a base 12 that mounts to the frame of the conveyor. Connected to each base 12 is a plurality of outer perch supports 14A and inner perch supports 14B for supporting three idler rollers 16A-C in a generally U-shaped configuration. As such, outer supports 14A located at each end of base 12 support one end of a shaft carrying outermost rollers 16A and 16C at a specified height above base 12, while inner supports 14B are positioned on base 12 to support the ends of a shaft carrying a central roller 16B as well as an opposite end of the shaft carrying rollers 16A and 16C at a height below the height of outer supports 14A relative to base 12.
At the feed end of the conveyor, material is deposited on the belt in a load zone that typically comprises a walled hopper that directs the material onto the belt. As the material strikes the belt, the belt is prone to sagging between adjacent idler assemblies, which can result in material falling off the belt in the load zone area. One known method for addressing this problem involves substituting the two outermost rollers of several idler supports in the load zone with one or more long support rails supported across the several idler supports, such as is disclosed in U.S. Pat. No. 5,350,053. While support rails extend along and support the belt edges in the load zone and prevent belt sagging, they have their drawbacks. For example, wear inevitably occurs on the material of the support rail in contact with the underside of the belt. This wear may be localized in only one portion of the support rail. As a result, replacement of the entire support rail is required. This replacement is difficult, time consuming and costly. Thus, there is a need to improve the support assembly for the load zone of a belt conveyor to overcome these drawbacks.